Tuesday, 13 March 2018

During the mobile world congress, I was pleasantly surprised to see how LoRa ecosystem keeps getting larger. There was also an upbeat mood within the LoRa vendor community as it keeps winning one battle after another. Here is my short take on the technology with an unbiased lens.

To start with, lets look at this short report by Tom Rebbeck from Analysys Mason. The PDF can be downloaded after registering from here.

As can be seen, all major IoT technologies (LoRa, NB-IoT, Sigfox & LTE-M) gained ground in 2017. Most of the LoRa and all of Sigfox networks are actually not deployed by the mobile operators. From the article:

These points lead to a final observation about network deployments – many operators are launching multiple technologies. Of the 26 operators with publicly-announced interest in LTE-M networks, 20 also have plans for other networks;• 14 will combine it with NB-IoT• four will offer LTE-M and LoRa and• two, Softbank and Swisscom, are working with LoRa, LTE-M and NB-IoT.We are not aware of operators also owning Sigfox networks, though some, such as Telefónica, are selling connectivity provided by a Sigfox network operator.The incremental cost of upgrading from NB-IoT or LTE-M to both technologies is relatively small. Most estimates put the additional cost at less than an additional 20% – and sometimes considerably less. For many operators, the question will be which technology to prioritise, and when to launch, rather than which to choose.The reasons for launching multiple networks appear to be tactical as much as strategic. Some operators firmly believe that the different technologies will match different use cases – for example, LoRa may be better suited to stationary, low bandwidth devices like smart meters, while LTE-M, could meet the needs of devices that need mobility, higher bandwidth and support for voice, for example a personal health monitor with an emergency call button.But, a fundamental motive for offering multiple networks is to hedge investments. While they may not admit it publicly, operators do not know which technology will gain the most traction. They do not want to lose significant, lucrative contracts because they have backed the wrong technology. Deploying both LTE-M and NB-IoT – or LoRa – adds little cost and yet provides a hedge against this risk. For operators launching LoRa, there has been the added benefit of being early to market and gaining experience of what developers want and need from LPWA networks. This experience should help them when other technologies are deployed at scale.

The following is from MWC 2018 summary by ABI Research:LPWA network technologies continue to gather momentum with adoption from a growing ecosystem of communications service providers (CSPs), original equipment manufacturers (OEMs) and IoT solution providers. LPWA networks are central to the connectivity offerings from telcos with support for NB-IoT, LTE-M, LoRaWAN, and SIGFOX. Telefonica highlighted SIGFOX as an important network technology along with NB-IoT and Cat M in its IoT connectivity platform. Similarly, Orange and SK Telecom emphasized on their continued support for LoRaWAN along with Cat M in France and South Korea. On the other hand, Vodafone and Deutsche Telekom, while aggressively pursuing deployment of NB-IoT networks, currently have mostly large scale POCs on their networks. ...Smart meters — Utilities are demanding that meter OEMs and technology solution providers deliver product design life of at least 15 years for battery operated smart water and gas meters. LPWA technologies, such as NB-IoT, LoRaWAN, SIGFOX and wireless M-bus, that are optimized for very low-power consumption and available at low cost are clearly emerging as the most favored LPWA solutions.

So someone recently asked me is LoRa is the new WiMax? The answer is obviously a big NO. Just look at the LoRa alliance members in the picture above. Its a whole ecosystem with different players having different interests, working on a different part of the ecosystem.

NB-IoT & LTE-M will gain ground in the coming years but there will always be a place for other LPWA technologies like LoRa.

Finally, here is a slide deck (embedded below) that I really like. The picture above very nicely illustrates that LoRaWAN and Cellular complement each other well. Maybe that is the reason that Orange is a big supporter of LoRa.

So for operators who are just starting their IoT journey or smaller operators who are unsure of the IoT potential, may want to start their journey with LoRa to play around and understand the business cases, etc. In the meantime LTE-M and NB-IoT ecosystem will mature with prices coming down further and battery time improving. That may be the right time to decide on the way forward.

Wednesday, 7 March 2018

This year at MWC, I took the time out to go and see as many companies as I can. My main focus was looking at connectivity solutions, infrastructure, devices, gadgets and anything else cool. I have to say that I wasn't too impressed. I found some of the things later on Twitter or YouTube but as it happens, one cannot see everything.

I have to be honest, haven't seen a WOW demo yet at #MWC18. While there are lots of interesting stuff, it's all the same, old and tired stuff.

I will be writing a blog on Small Cells, Infrastructure, etc. later on but here are some cool videos that I have found. As its a playlist, if I find any more, it will be added to the same playlist below.

The big vendors did not open up their stands for everyone (even I couldn't get in 😉) but the good news is that most of their demos is available online. Below are the name of the companies that had official MWC 2018 websites. Will add more when I find them.

Thursday, 12 October 2017

In an earlier post I discussed briefly about the sidelink: V2V communications are based on D2D communications defined as part of ProSe services in Release 12 and Release 13 of the specification. As part of ProSe services, a new D2D interface (designated as PC5, also known as sidelink at the physical layer) was introduced and now as part of the V2V WI it has been enhanced for vehicular use cases, specifically addressing high speed (up to 250Kph) and high density (thousands of nodes).

Before going further, lets just quickly recap the different V2x abbreviations:

V2X = Vehicle-to-Everything

V2V = Vehicle-to-Vehicle

V2I = Vehicle-to-Infrastructure

V2P = Vehicle-to-Pedestrian

V2H = Vehicle-to-Home

eV2X = enhanced Vehicle-to-Everything

I came across this interesting presentation from ITRI that provides lot more details on sidelink and its proposed extension to other topics including eV2X and FeD2D (Further enhanced Device-to-Device).

There are quite a few references in the document that provides more details on sidelink and its operation and extension to other devices like wearables.

There are also details on synchronization and eV2X services.

There is also a very nice D2D overview presentation by Orange that I am embedding below (download from slideshare)

Monday, 1 May 2017

I have seen many people wondering if so many different types of IoT technologies are needed, 3GPP or otherwise. The story behind that is that for many years 3GPP did not focus too much on creating an IoT variant of the standards. Their hope was that users will make use of LTE Cat 1 for IoT and then later on they created LTE Cat 0 (see here and here).

The problem with this approach was that the market was ripe for a solution to a different types of IoT technologies that 3GPP could not satisfy. The table below is just an indication of the different types of technologies, but there are many others not listed in here.

The most popular IoT (or M2M) technology to date is the humble 2G GSM/GPRS. Couple of weeks back Vodafone announced that it has reached a milestone of 50 million IoT connections worldwide. They are also adding roughly 1 million new connections every month. The majority of these are GSM/GPRS.

Different operators have been assessing their strategy for IoT devices. Some operators have either switched off or are planning to switch off they 2G networks. Others have a long term plan for 2G networks and would rather switch off their 3G networks to refarm the spectrum to more efficient 4G. A small chunk of 2G on the other hand would be a good option for voice & existing IoT devices with small amount of data transfer.

In fact this is one of the reasons that in Release-13 GSM is being enhanced for IoT. This new version is known as Extended Coverage – GSM – Internet of Things (EC-GSM-IoT ). According to GSMA, "It is based on eGPRS and designed as a high capacity, long range, low energy and low complexity cellular system for IoT communications. The optimisations made in EC-GSM-IoT that need to be made to existing GSM networks can be made as a software upgrade, ensuring coverage and accelerated time to-market. Battery life of up to 10 years can be supported for a wide range use cases."

The most popular of the non-3GPP IoT technologies are Sigfox and LoRa. Both these technologies have gained significant ground and many backers in the market. This, along with the gap in the market and the need for low power IoT technologies that transfer just a little amount of data and has a long battery life motivated 3GPP to create new IoT technologies that were standardised as part of Rel-13 and are being further enhanced in Rel-14. A summary of these technologies can be seen below

If you look at the first picture on the top (modified from Qualcomm's original here), you will see that these different IoT technologies, 3GPP or otherwise address different needs. No wonder many operators are using the unlicensed LPWA IoT technologies as a starting point, hoping to complement them by 3GPP technologies when ready.

Finally, looks like there is a difference in understanding of standards between Ericsson and Huawei and as a result their implementation is incompatible. Hopefully this will be sorted out soon.

Market Status:

Telefonica has publicly said that Sigfox is the best way forward for the time being. No news about any 3GPP IoT technologies.

Friday, 7 October 2016

I have been covering the LTE Voice Summit for last couple of years (see here: 2015 & 2014) but this year I wont be around unfortunately. Anyway, I am sure there will be many interesting discussions. From my point of view, the 2 topics that have been widely discussed is roaming and VoWiFi.

One of the criticisms of VoWiFi is that it does not the QoS aspect is missing, which makes VoLTE special. In a recent post, I looked at the QoS in VoWiFi issue. If you haven't seen it, see here.

Coming back to VoLTE roaming, I came across this recent presentation by Orange.

This suggests that S8HR is a bad idea, the focus should be on LBO. For anyone who is not aware of the details of S8HR & LBO, please see my earlier blog post here. What this presentation suggests is to use LBO with no MTR (Mobile Termination Rates) but instead use TAP (Transferred Account Procedures). The presentation is embedded below:

Another approach that is not discussed too much but seems to be the norm at the moment is the use of IP eXchange (IPX). I also came across this other panel discussion on the topic

IPX is already in use for data roaming today and acts as a hub between different operators helping to solve inter-operability issues and mediating between roaming models. It can work out based on the calling and callee party what kind of quality and approach to use.

Here is the summary of the panel discussion:

Hopefully the LTE Voice Summit next week will provide some more insights. I look forward to hearing them.

Monday, 21 September 2015

3GPP held a 5G Workshop in Phoenix last week. 550 delegates and over 70 presentations contributed to the discussion, which covered the full range of requirements that will feed TSG RAN work items for the next five years. I will eventually look at all the presentations and highlight the ones that I find interesting as a part of this blog. Due to the vast number of presentations, I will split them into a few blog posts.

Lets start with the chairman summary. The chair highlighted three high level use cases that 5G needs to address (This has been highlighted in many presentations, see here for example):

Enhanced Mobile Broadbandare

Massive Machine Type Communications

Ultra-reliable and Low Latency Communications

As can be seen in the picture above, 3GPP is planning to split the 5G work into two phases. Phase 1 (Rel-15) will look at a subset of requirements that are important for the commercial needs of the day. Phase 2 (Rel-16) will look at more features, use cases, detailed requirements, etc.

Here is the chair summary of the workshop:

The presentation (RWS-150002) from Motorola/Lenovo highlighted the need to handle different spectrum. For sub-6GHz, the existing air interface could work with slight modifications. For spectrum between 6GHz and 30GHz, again a similar air interface like 4G may be good enough but for above 30GHz, there is a need for new one die to phase noise.

The presentation by CATT or China Academy of Telecommunication Technology (RWS-150003) is quite interesting and is embedded below. They also propose Pattern Division Multiple Access (PDMA).

Orange (RWS-150004) has definitely put a thought into what good 5G would be. Their presentation is embedded below too:

The presentation from Huawei (RWS-150006) introduced the concept of Unified Air Interface, UAI.

They presentation also explains the concept of Adaptive Frame structures and RAN slicing very well. For those who may be wondering, uMTC stands for ultra-reliable MTC and mMTC stands for massive MTC. RAN slicing enables the RAN to be partitioned such that a certain amount of carriers are always dedicated to a certain services independently of other services. This ensures that the service in the slice is always served reliably.

The final presentation is the vision and priorities by 5GPPP as follows:

Wednesday, 21 January 2015

VoWiFi is certainly a hot topic, thanks to the support of VoWiFi on iPhone 6. A presentation from LTE World Summit 2014 by Taqua on this topic has already crossed 13K views. In this post I intend to look at the different approaches for VoWiFi and throw in some technical details. I am by no means an expert so please feel free to add your input in the comments.

Anybody reading this post is not aware of S2a, S2b, Samog, TWAG, ePDG, etc. and what they are, please refer to our whitepaper on cellular and wi-fi integration here (section 3).

There are two approaches to VoWiFi, native client already in your device or an App that could be either downloaded from the app store or pre-installed. The UK operator '3' has an app known as ThreeInTouch. While on WiFi, this app can make and receive calls and texts. The only problem is that it does not handover an ongoing call from WiFi to cellular and and vice versa. Here are a few slides (slides 36-38) from them from a conference last year:

The other operators have a native client that can use Wi-Fi as the access network for voice calls as well as the data when the device is connected on the WLAN.

A simple architecture can be seen from the picture above. As can be seen, the device can connect to the network via a non-3GPP trusted wireless access network via the TWAG or via a non-3GPP untrusted wireless access network via ePDG. In the latter case, an IPSec tunnel would have to be established between the device and the ePDG. The SIM credentials would be used for authentication purposes so that an intruder cannot access ePDG and the core.

Now, I dont want to talk about VoLTE bearers establishment, etc. which I have already done here earlier. In order to establish S2a (trusted) and S2b (untrusted) connection, the AAA server selects an APN among those which are subscribed to in the HLR/HSS. The PDN-GW (generally referred to as PGW) dynamically assigns an IP address out of a pool of addresses which is associated with this APN. This UE IP address is used by the VoWiFi SIP UA (User Agent) as the contact information when registering to the SIP soft switch (which would typically be the operators IMS network).

If for any reason the SIP UA in the device is not able to use the SIM for authentication (needs ISIM?) then a username/password based authentication credentials can be used (SIP digest authentication).

Typically, there would be a seperate UA for VoLTE and VoWiFi. They would both be generally registering to the same IMS APN using different credentials and contact addresses. The IMS network can deal with multiple registrations from the same subscriber but from different IP addresses (see 3GPP TS 23.237 - 'IMS Service Continuity' for details).

Because of multiple UA's, a new element needs to be introduced in order to 'fork' the downstream media streams (RTP/RTCP packets) to different IP addresses over time.

3GPP has defined the Access Transfer Gateway (ATGW) which is controlled by the Access Transfer Control Function (ATCF); the ATCF interfaces to the IMS and Service Centralization and Continuity Application Server (SCC AS). All these are not shown in the picture above but is available in 3GPP TS 23.237. The IMS networks in use today as well as the one being deployed for VoLTE does not have ATGW/ATCF. As a result vendors have to come up with clever non-standardised solutions to solve the problem.

When there is a handover between 3GPP and non-3GPP networks, the UE IP address needs to be preserved. Solutions like MIP and IPSec have been used in the past but they are not flexible. The Release-12 solution of eSAMOG (see 3GPP TS 23.402) can be used but the solution requires changes in the UE. For the time being we will see proprietary solutions only but hopefully in future there would be standardised solutions available.

3GPP TS 23.234 describes more in detail the interworking of 3GPP based system and WLAN. Interested readers can refer to that for further insight.

Wednesday, 28 May 2014

The last post on Network sharing by NEC was surprisingly popular so I thought its worth doing a case study by Orange in Poland on how they successfully managed to share their network with T-Mobile. Full presentation embedded as follows:

Monday, 12 August 2013

I came across this interesting presentation from Orange in the LTE World Summit this year where the authors have detailed the C-RAN architecture and also discussing the fronthaul challenges faced by C-RAN. The presentation is embedded as follows. Please feel free to add your comments with your opinions.

The last table is from an Ofcom document here. Its very interesting read. For example I didnt know that The L-band was the first major part of Ofcom spectrum awards programme relevant to mobile services. It consists of 40MHz between 1452MHz and 1492MHz. The auction took place in May 2008, in which Qualcomm won the entirety of the available spectrum.

Here is the summary of the operators working on LTE:

Everything Everywhere (EE = Orange + T-Mobile) - They are calling their '4G' service as EE, covering up to 70% of the UK by the end of 2013. Network kit provided by Huawei.

Three - Samsung will provide the Radio Access Network, and the core infrastructure, for Three's LTE (4G) network. That includes the base stations, and radio core. 3 UK has agreed to purchase 2 x 15 MHz of 1800 MHz spectrum from Everything everywhere, and plans commercial launch of LTE service in 2013.

Telefonica (O2) trial network - Equipment supplied by Nokia Siemens Networks (NSN) for both the Radio and Core network elements. Backhaul for the 4G trial network has been provided using Microwave Radio Equipment from Cambridge Broadband Networks Limited, NEC and Nokia Siemens Networks.

Updated 13/09/12 - 11:25

UK Broadband rolled out the first commercial TD-LTE network in London back in February (available to customers since May 2012). The equipment is provided by Huawei. They have 40MHz in Band 42 (3.5GHz) and 84MHz in band 43 (3.6GHz).